Assistive Technology Compatibility and Testing
Assistive technology (AT) testing verifies that real user agents can perceive, operate, and understand the interface. Automated tools catch only a subset of issues-often estimated around a third-so combine automated scans, manual checks, and AT testing.
Test matrix
- Screen readers: NVDA with Firefox/Chrome, JAWS with Chrome/Edge, VoiceOver with Safari, TalkBack with Chrome, Narrator with Edge. Pick representative combos, not every permutation.
- Keyboard only: Tab/Shift+Tab, Enter/Space, arrows, Escape; verify visible focus order and no traps.
- Zoom and reflow: 200% and 400% zoom; 320 CSS px width without two-dimensional scrolling except for data tables/maps; text spacing overrides.
- Forced colors/high contrast, reduced motion, touch target size, voice control (label-in-name), switch or eye-gaze where relevant.
Worked example
Test a disclosure: focus the trigger, press Enter and Space, confirm the panel opens, aria-expanded changes true/false, focus remains on the trigger, and the screen reader announces "expanded/collapsed." Reasoning: visual opening is not enough; state must be exposed and keyboard-operable. If the panel is removed from the DOM, re-check focus.
Traps
Declaring success because axe reports zero violations; testing with one screen reader and one browser; skipping keyboard-only checks; not resetting zoom between tests; ignoring mobile AT; and using a mouse to verify hover-only content.
Documentation
Record browser, AT, version, OS, and steps; reproducible bugs get fixed faster.